Previously, many types of pool cleaners have been used in endeavoring to provide an effective means for producing a momentary interruption of the pool pump intake flow to propel a cleaner around the bottom of a swimming pool, while automatically removing debris and foreign matter by the suction of the pool pump.
Prior art is replete with structure utilizing valves that cause the interruption of induced flow due to kinetic energy of the water flow transferring force to the valve using the inertia of the fluid, which in turn, promotes linear movement of the cleaner through pulsation. Various types of valves have been employed in the past for this function, which include flappers, flexible diaphragms, flexible jaws, bellows, ball type, and elastomeric jaws. In any event, these devices developed by prior art all use the suction flow created by conventional swimming pool filtration equipment. Water flow under negative pressure is intermittently interrupted by the above mentioned valve mechanism resulting in a step-like movement of the cleaner in a random fashion across the bottom and sides of swimming pool surfaces.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention, however, the following U.S. patents are considered related:
______________________________________ Patent No. Inventor Issue Date ______________________________________ 4,023,227 Chauvier May 17, 1977 4,351,077 Hofmann Sep. 28, 1982 4,642,833 Stoltz et al Feb. 17, 1987 4,742,593 Kallenbach May 10, 1988 4,761,848 Hofmann Aug. 9, 1988 4,769,867 Stoltz Sep. 13, 1988 4,807,318 Kallenbach Feb. 28, 1989 4,817,225 Stoltz Apr. 4, 1989 4,949,419 Kallenbach Aug. 21, 1990 5,014,382 Kallenbach May 14, 1991 5,033,148 Chauvier et al Jul. 23, 1991 5,265,297 Gould et al Nov. 30, 1993 5,315,728 Atkins May 31, 1994 5,337,433 Gould et al Aug. 16, 1994 5,384,928 Khoury Jan. 31, 1995 5,440,645 Atkins Sep. 19, 1995 ______________________________________
U.S. Pat. Nos. 4,023,227, 4,351,077 and 5,033,148 teach a flapper valve that is pivotally displaced to automatically transfer flow from one passage to another. In some cases a bypass valve is required to regulate the suction pressure applied to the apparatus and in '148 an auxiliary inlet is utilized to accommodate the volume of fluid flow through the pool pump.
A flexible diaphragm valve is utilized in U.S. Pat. Nos. 4,642,833, 4,742,593, 4,761,848, 5,315,728 and 5,450,645 which consists of a resilient tube that is reduced in cross-section in the middle, with external or internal ribs for controlling it's flexibility. In all cases, the diaphragm is closed due to the negative pressure of the pump overcoming the resistance of the flexural walls pulling the walls together to impede the flow. Pressure equalization on the outside of the diaphragm permits opening, and various methods are employed to accomplish this function, such as spring loading, etc.
U.S. Pat. Nos. 4,769,867, 5,265,297 and 5,384,928 disclose a valve having jaw-like lips of a flexible material biased in an open position by it's inherent elasticity and resiliency. The lips close under negative pressure and reopen by the material establishing it's inherent memory.
The physical characteristics of the flexible disc and stop arrangement are presented in U.S. Pat. Nos. 4,949,419 and 5,014,382 for background purposes.
Kallenbach in U.S. Pat. No. 4,807,318 employs a spring loaded bellows-like diaphragm and a rigid unrestricted outlet passageway for flow interruption and cycling.
A spherical closure member having a specific gravity slightly greater than the liquid causes interruption by moving freely toward and away from the valve seat in U.S. Pat. No. 4,817,225.
U.S. Pat. No. 5,337,433 is the prior art upon which the instant invention is an improvement. Gould et al teach a valve having an entrance mouth with one or more single acting closure lips formed of thin metal spring material. The lips are drawn into full closure by the suction of the pool pump and open when the bias is substantially less than the closing force. No bumpers, weights, nets, or floats are used to assist in balance efficiency. Partial flow of the pump is utilized in the apparatus at a specific design flow rate.